nbd patches for 2017-08-15

- Eric Blake: nbd: Fix trace message for disconnect
 - Stefan Hajnoczi: qemu-iotests: step clock after each test iteration
 - Fam Zheng: 0/4 block: Fix non-shared storage migration
 - Eric Blake: nbd-client: Fix regression when server sends garbage
 -----BEGIN PGP SIGNATURE-----
 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg
 
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Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-08-15' into staging

nbd patches for 2017-08-15

- Eric Blake: nbd: Fix trace message for disconnect
- Stefan Hajnoczi: qemu-iotests: step clock after each test iteration
- Fam Zheng: 0/4 block: Fix non-shared storage migration
- Eric Blake: nbd-client: Fix regression when server sends garbage

# gpg: Signature made Tue 15 Aug 2017 16:06:02 BST
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-08-15:
  nbd-client: Fix regression when server sends garbage
  iotests: Add non-shared storage migration case 192
  block-backend: Defer shared_perm tightening migration completion
  nbd: Fix order of bdrv_set_perm and bdrv_invalidate_cache
  stubs: Add vm state change handler stubs
  qemu-iotests: step clock after each test iteration
  nbd: Fix trace message for disconnect

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

block/block-backend.c

@@ -20,6 +20,7 @@
 #include "qapi-event.h"
 #include "qemu/id.h"
 #include "trace.h"
+#include "migration/misc.h"
 
 /* Number of coroutines to reserve per attached device model */
 #define COROUTINE_POOL_RESERVATION 64
@@ -68,6 +69,7 @@ struct BlockBackend {
     NotifierList remove_bs_notifiers, insert_bs_notifiers;
 
     int quiesce_counter;
+    VMChangeStateEntry *vmsh;
 };
 
 typedef struct BlockBackendAIOCB {
@@ -129,6 +131,23 @@ static const char *blk_root_get_name(BdrvChild *child)
     return blk_name(child->opaque);
 }
 
+static void blk_vm_state_changed(void *opaque, int running, RunState state)
+{
+    Error *local_err = NULL;
+    BlockBackend *blk = opaque;
+
+    if (state == RUN_STATE_INMIGRATE) {
+        return;
+    }
+
+    qemu_del_vm_change_state_handler(blk->vmsh);
+    blk->vmsh = NULL;
+    blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    }
+}
+
 /*
  * Notifies the user of the BlockBackend that migration has completed. qdev
  * devices can tighten their permissions in response (specifically revoke
@@ -147,6 +166,24 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
 
     blk->disable_perm = false;
 
+    blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        blk->disable_perm = true;
+        return;
+    }
+
+    if (runstate_check(RUN_STATE_INMIGRATE)) {
+        /* Activation can happen when migration process is still active, for
+         * example when nbd_server_add is called during non-shared storage
+         * migration. Defer the shared_perm update to migration completion. */
+        if (!blk->vmsh) {
+            blk->vmsh = qemu_add_vm_change_state_handler(blk_vm_state_changed,
+                                                         blk);
+        }
+        return;
+    }
+
     blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
@@ -291,6 +328,10 @@ static void blk_delete(BlockBackend *blk)
     if (blk->root) {
         blk_remove_bs(blk);
     }
+    if (blk->vmsh) {
+        qemu_del_vm_change_state_handler(blk->vmsh);
+        blk->vmsh = NULL;
+    }
     assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers));
     assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers));
     QTAILQ_REMOVE(&block_backends, blk, link);

block/nbd-client.c

@@ -73,7 +73,7 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)
     int ret;
     Error *local_err = NULL;
 
-    for (;;) {
+    while (!s->quit) {
         assert(s->reply.handle == 0);
         ret = nbd_receive_reply(s->ioc, &s->reply, &local_err);
         if (ret < 0) {
@@ -107,6 +107,9 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)
         qemu_coroutine_yield();
     }
 
+    if (ret < 0) {
+        s->quit = true;
+    }
     nbd_recv_coroutines_enter_all(s);
     s->read_reply_co = NULL;
 }
@@ -135,6 +138,10 @@ static int nbd_co_send_request(BlockDriverState *bs,
     assert(i < MAX_NBD_REQUESTS);
     request->handle = INDEX_TO_HANDLE(s, i);
 
+    if (s->quit) {
+        qemu_co_mutex_unlock(&s->send_mutex);
+        return -EIO;
+    }
     if (!s->ioc) {
         qemu_co_mutex_unlock(&s->send_mutex);
         return -EPIPE;
@@ -143,7 +150,7 @@ static int nbd_co_send_request(BlockDriverState *bs,
     if (qiov) {
         qio_channel_set_cork(s->ioc, true);
         rc = nbd_send_request(s->ioc, request);
-        if (rc >= 0) {
+        if (rc >= 0 && !s->quit) {
             ret = nbd_rwv(s->ioc, qiov->iov, qiov->niov, request->len, false,
                           NULL);
             if (ret != request->len) {
@@ -154,6 +161,9 @@ static int nbd_co_send_request(BlockDriverState *bs,
     } else {
         rc = nbd_send_request(s->ioc, request);
     }
+    if (rc < 0) {
+        s->quit = true;
+    }
     qemu_co_mutex_unlock(&s->send_mutex);
     return rc;
 }
@@ -168,8 +178,7 @@ static void nbd_co_receive_reply(NBDClientSession *s,
     /* Wait until we're woken up by nbd_read_reply_entry.  */
     qemu_coroutine_yield();
     *reply = s->reply;
-    if (reply->handle != request->handle ||
-        !s->ioc) {
+    if (reply->handle != request->handle || !s->ioc || s->quit) {
         reply->error = EIO;
     } else {
         if (qiov && reply->error == 0) {

block/nbd-client.h

@@ -29,6 +29,7 @@ typedef struct NBDClientSession {
 
     Coroutine *recv_coroutine[MAX_NBD_REQUESTS];
     NBDReply reply;
+    bool quit;
 } NBDClientSession;
 
 NBDClientSession *nbd_get_client_session(BlockDriverState *bs);

nbd/common.c

@@ -182,7 +182,7 @@ const char *nbd_cmd_lookup(uint16_t cmd)
     case NBD_CMD_WRITE:
         return "write";
     case NBD_CMD_DISC:
-        return "discard";
+        return "disconnect";
     case NBD_CMD_FLUSH:
         return "flush";
     case NBD_CMD_TRIM:

nbd/server.c

@@ -1045,11 +1045,22 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
                           bool writethrough, BlockBackend *on_eject_blk,
                           Error **errp)
 {
+    AioContext *ctx;
     BlockBackend *blk;
     NBDExport *exp = g_malloc0(sizeof(NBDExport));
     uint64_t perm;
     int ret;
 
+    /*
+     * NBD exports are used for non-shared storage migration.  Make sure
+     * that BDRV_O_INACTIVE is cleared and the image is ready for write
+     * access since the export could be available before migration handover.
+     */
+    ctx = bdrv_get_aio_context(bs);
+    aio_context_acquire(ctx);
+    bdrv_invalidate_cache(bs, NULL);
+    aio_context_release(ctx);
+
     /* Don't allow resize while the NBD server is running, otherwise we don't
      * care what happens with the node. */
     perm = BLK_PERM_CONSISTENT_READ;
@@ -1087,15 +1098,6 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
         exp->eject_notifier.notify = nbd_eject_notifier;
         blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
     }
-
-    /*
-     * NBD exports are used for non-shared storage migration.  Make sure
-     * that BDRV_O_INACTIVE is cleared and the image is ready for write
-     * access since the export could be available before migration handover.
-     */
-    aio_context_acquire(exp->ctx);
-    blk_invalidate_cache(blk, NULL);
-    aio_context_release(exp->ctx);
     return exp;
 
 fail:

stubs/Makefile.objs

@@ -19,6 +19,7 @@ stub-obj-y += is-daemonized.o
 stub-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 stub-obj-y += machine-init-done.o
 stub-obj-y += migr-blocker.o
+stub-obj-y += change-state-handler.o
 stub-obj-y += monitor.o
 stub-obj-y += notify-event.o
 stub-obj-y += qtest.o

stubs/change-state-handler.c

@@ -0,0 +1,14 @@
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "sysemu/sysemu.h"
+
+VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb,
+                                                     void *opaque)
+{
+    return NULL;
+}
+
+void qemu_del_vm_change_state_handler(VMChangeStateEntry *e)
+{
+    /* Nothing to do. */
+}

tests/qemu-iotests/093

@@ -133,6 +133,10 @@ class ThrottleTestCase(iotests.QMPTestCase):
             self.assertTrue(check_limit(params['iops_rd'], rd_iops))
             self.assertTrue(check_limit(params['iops_wr'], wr_iops))
 
+        # Allow remaining requests to finish.  We submitted twice as many to
+        # ensure the throttle limit is reached.
+        self.vm.qtest("clock_step %d" % ns)
+
     # Connect N drives to a VM and test I/O in all of them
     def test_all(self):
         params = {"bps": 4096,

tests/qemu-iotests/192

@@ -0,0 +1,63 @@
+#!/bin/bash
+#
+# Test NBD export with -incoming (non-shared storage migration use case from
+# libvirt)
+#
+# Copyright (C) 2017 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=famz@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt generic
+_supported_proto file
+_supported_os Linux
+
+if [ "$QEMU_DEFAULT_MACHINE" != "pc" ]; then
+    _notrun "Requires a PC machine"
+fi
+
+size=64M
+_make_test_img $size
+
+{
+echo "nbd_server_start unix:$TEST_DIR/nbd"
+echo "nbd_server_add -w drive0"
+echo "q"
+} | $QEMU -nodefaults -display none -monitor stdio \
+    -drive format=$IMGFMT,file=$TEST_IMG,if=ide,id=drive0 \
+    -incoming defer 2>&1 | _filter_testdir | _filter_qemu | _filter_hmp
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/192.out

@@ -0,0 +1,7 @@
+QA output created by 192
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) nbd_server_start unix:TEST_DIR/nbd
+(qemu) nbd_server_add -w drive0
+(qemu) q
+*** done

tests/qemu-iotests/group

@@ -186,3 +186,4 @@
 188 rw auto quick
 189 rw auto
 190 rw auto quick
+192 rw auto quick